The present invention relates to a flat knitting machine with transfer mechanism comprising a transfer jack bed (hereinafter it is referred to as xe2x80x9cTR jack bedxe2x80x9d) in which a number of transfer jacks (hereinafter they are referred to as xe2x80x9cTR jackxe2x80x9d) each having a loop retaining portion at a front end thereof are embedded and which is arranged over needle beds, and a transfer cam mechanism for transferring the loop between the TR jacks of the TR jack bed and the knitting needles of the needle beds.
A flat knitting machine comprising a pair of front and back needle beds holding knitting needles in such a manner as to be advanced and retracted in needle grooves formed on upper surfaces of the needle beds, at least either of which is racked horizontally with respect to the opposite needle bed, and at least one transfer jack bed located over the at least one needle bed and holding transfer jacks in such a manner as to freely advance and retract in the grooves formed on an upper surface thereof is known from Japanese Patent No. 2794144. In the flat knitting machine disclosed by this publication, the TR jack bed and the needle beds are structured so that they can be racked longitudinally relative to each other to transfer a loop between the knitting needles of the front and back needle beds and between the knitting needle of the needle bed and the TR jack of the TR jack bed. The flat knitting machine thus structured enables a loop retained by the knitting needle of the needle bed to be transferred to an adjacent needle of the same needle bed by transferring the loop retained by the knitting needle of the needle bed to the TR jack of the TR jack bed, first; then racking the TR jack bed; and then transferring the loop retained by the TR jack to the adjacent needle of the needle bed.
Japanese Laid-open (Unexamined) Patent Publication No. Hei 11 (1999)-1850 discloses a flat knitting machine with a transfer mechanism which is structured so that when a loop retaining portion of the TR jack is retracted across a loop retained on the TR jack to transfer the loop to a knitting needle, the TR jack can be retracted while keeping its front end in the depressed state.
In the flat knitting machine disclosed by the publication of Japanese Patent No. 2794144 cited above, the TR jack is advanced and retracted linearly in the horizontal direction on a level higher than a front end of the needle bed. Due to this, when the loop retained on the TR jack is transferred to the knitting needle, the loop is stretched and elongated to deteriorate the quality of the knitted fabric.
To solve this problem involved in the publication of Japanese Patent No. 2794144, the flat knitting machine disclosed in Japanese Laid-open (Unexamined) Patent Publication No. Hei 11 (1999)-1850 is structured so that when the loop retaining portion of the TR jack is retracted across the loop retained on the TR jack to transfer the loop to the knitting needle, the TR jack can be retracted, while keeping its front end in the depressed state, to reduce the load on the loop.
However, both of the flat knitting machines disclosed by the publications cited above are structured so that when the TR jack is in its advanced position over the needle bed gap between the needle beds, the TR jack can be positioned on a level higher than the front ends of the needle beds, in order to avoid interference with the knitting needle and the sinker plate on the needle bed when racked. In this structure, the loop retaining portion at the front end of the TR jack cannot be swung vertically in the advanced position of the TR jack. Due to this, a load is put on the loop retained on the loop retaining portion of the TR jack in the advanced position of the TR jack.
In the light of the problems mentioned above, the present invention has been made. It is an object of the invention to provide a flat knitting machine with a transfer mechanism wherein when the loop retaining portion of the TR jack is in its advanced position, the loop retaining position of the TR jack can be held in its raised position or released therefrom in a selective manner and also can be lowered an increased distance to further reduce the load on the loop.
The present invention provides a flat knitting machine with a loop transfer mechanism comprising a pair of front and back needle beds, arranged in a confronting relation and holding knitting needles in such a manner as to freely advance and retract in grooves formed in upper surfaces of the needle beds, at least one of which is racked relative to the opposite needle bed, and at least one transfer jack bed, provided over the at least one needle bed and holding transfer, jacks, each having a loop retaining portion at a front end portion thereof, in such a manner as to freely advance and retract in grooves formed in upper surface of the at least one transfer jack bed,
wherein the transfer jack is structured so that when the loop retaining portion is advanced to an advanced position over a needle bed gap between the front and back needle beds, the loop retaining portion can be held in such a manner as to swing between its raised position and its lowered position;
wherein there is provided transfer jack holding means for holding the loop retaining portion in its raised position at least as high as a level to avoid interference with knitting members arranged on the needle beds while the needle bed is racked, when the loop retaining portion of the transfer jack retaining a loop thereon is in the advanced position; and
wherein there is provided transfer jack controlling means for controlling the transfer jack holding means to selectively hold the loop retaining portion of the transfer jack in its raised position and release it from its held state.
wherein the transfer jack holding means includes a transfer jack controlling member which is fitted in a recess formed in the transfer jack bed in a freely advance-and-retract manner;
wherein the transfer jack controlling member and the transfer jack are brought into engagement with each other by their relative movement in the advancing-and-retracting direction, whereby the loop retaining portion of the transfer jack is held in its raised position when the loop retaining portion is in its advanced position; and
wherein when the loop retaining portion is in the advanced position, the transfer jack controlling member is moved to release the engagement between the transfer jack controlling member and the transfer jack, so as to allow the loop retaining portion of the transfer jack to be lowered.
It is preferable that the recess is formed on a top surface of the transfer jack and the transfer jack controlling member is slidably fitted in the recess; wherein the recess has an engaging portion, formed at a bottom of the recess at a rear end portion thereof, to engage with a rear end portion of the transfer jack controlling member; wherein a notch for the rear end portion of the transfer jack controlling member to be inserted into so as to allow the transfer jack to swing is formed in the bottom of the recess at a location forward of the engaging portion; and wherein the transfer jack controlling means puts the transfer jack controlling member in a location at a rear of the recess to bring the transfer jack and the transfer jack controlling member into engagement with each other and puts the transfer jack controlling member in a location at a front of the recess to release the engagement between the transfer jack and the transfer jack controlling member.
It is preferable that the transfer jack holding means includes a transfer jack controlling member which is fitted in a recess formed in the transfer jack bed in a freely advance-and-retract manner; wherein the transfer jack controlling member and the transfer jack are brought into engagement with each other by their relative movement in the advancing-and-retracting direction, whereby the loop retaining portion of the transfer jack is held in its raised position when the loop retaining portion is in its advanced position; and wherein when the loop retaining portion is in the advanced position, the transfer jack controlling member is moved to release the engagement between the transfer jack controlling member and the transfer jack, so as to allow the loop retaining portion of the transfer jack to be lowered.
It is preferable that the recess is formed on a top surface of the transfer jack and the transfer jack controlling member is slidably fitted in the recess; wherein the recess has an engaging portion, formed at a bottom of the recess at a rear end portion thereof, to engage with a rear end portion of the transfer jack controlling member; wherein a notch for the rear end portion of the transfer jack controlling member to be inserted into so as to allow the transfer jack to swing is formed in the bottom of the recess at a location forward of the engaging portion; and wherein the transfer jack controlling means puts the transfer jack controlling member in a location at a rear of the recess to bring the transfer jack and the transfer jack controlling member into engagement with each other and puts the transfer jack controlling member in a location at a front of the recess to release the engagement between the transfer jack and the transfer jack controlling member.